Electrostatic Self-Assembly Technique for Parallel Precision Alignment of Optical Devices

In precision assembly, the cost of machine technology increases significantly when high assembly accuracy is required (<15 μm). One reason is that higher accuracy with conventional automation technology requires much more precise and expensive machine components, such as bearings and actuators. Electrostatic self-assembly is a technique for the automatic alignment of micro-components without the need for precise machines and thus has the potential to reduce fabrication costs significantly. With this technique, electrodes are placed on the micro-components and the substrate. A low viscosity fluid is applied to the substrate and the components are roughly positioned. One pair of electrodes on the component faces one pair of electrodes on the substrate, equivalent to plate capacitors connected in series. If an alternating voltage is applied to the substrate electrodes, an electric field is formed. This results in electrostatic attraction in the transversal and lateral direction, which leads to an alignment of the components on the substrate. In this paper, we describe the structure design process for electrostatic self-assembly. Instead of micro-components, we use a rectangular glass wafer with a length of 125 mm. Within two test series, we prove that the existing technique is also suitable for a larger scale.